Improve a few things in pg_walinspect

This improves a few things in pg_walinspect:
- Return NULL rather than empty strings in pg_get_wal_records_info() for
the block references and the record description if there is no
information provided by the fallback.  This point has been raised by
Peter Geoghegan.
- Add a check on XLogRecHasAnyBlockRefs() for pg_get_wal_block_info(),
to directly skip records that have no block references.  This speeds up
the function a bit, depending on the number of records that have no
block references.

Author: Bharath Rupireddy
Reviewed-by: Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACWL9RG8sGJHinggRNBTxgRWJTSxCkB+cE6=t3Phh=Ey+A@mail.gmail.com
This commit is contained in:
Michael Paquier 2023-03-27 13:15:04 +09:00
parent 850f4b4c8c
commit 0276ae42dd
1 changed files with 27 additions and 15 deletions

View File

@ -186,8 +186,6 @@ GetWALRecordInfo(XLogReaderState *record, Datum *values,
RmgrData desc;
uint32 fpi_len = 0;
StringInfoData rec_desc;
StringInfoData rec_blk_ref;
uint32 main_data_len;
int i = 0;
desc = GetRmgr(XLogRecGetRmid(record));
@ -199,12 +197,6 @@ GetWALRecordInfo(XLogReaderState *record, Datum *values,
initStringInfo(&rec_desc);
desc.rm_desc(&rec_desc, record);
/* Block references. */
initStringInfo(&rec_blk_ref);
XLogRecGetBlockRefInfo(record, false, true, &rec_blk_ref, &fpi_len);
main_data_len = XLogRecGetDataLen(record);
values[i++] = LSNGetDatum(record->ReadRecPtr);
values[i++] = LSNGetDatum(record->EndRecPtr);
values[i++] = LSNGetDatum(XLogRecGetPrev(record));
@ -212,10 +204,26 @@ GetWALRecordInfo(XLogReaderState *record, Datum *values,
values[i++] = CStringGetTextDatum(desc.rm_name);
values[i++] = CStringGetTextDatum(id);
values[i++] = UInt32GetDatum(XLogRecGetTotalLen(record));
values[i++] = UInt32GetDatum(main_data_len);
values[i++] = UInt32GetDatum(XLogRecGetDataLen(record));
values[i++] = UInt32GetDatum(fpi_len);
values[i++] = CStringGetTextDatum(rec_desc.data);
values[i++] = CStringGetTextDatum(rec_blk_ref.data);
if (rec_desc.len > 0)
values[i++] = CStringGetTextDatum(rec_desc.data);
else
nulls[i++] = true;
/* Block references. */
if (XLogRecHasAnyBlockRefs(record))
{
StringInfoData rec_blk_ref;
initStringInfo(&rec_blk_ref);
XLogRecGetBlockRefInfo(record, false, true, &rec_blk_ref, &fpi_len);
values[i++] = CStringGetTextDatum(rec_blk_ref.data);
}
else
nulls[i++] = true;
Assert(i == ncols);
}
@ -377,6 +385,11 @@ pg_get_wal_block_info(PG_FUNCTION_ARGS)
while (ReadNextXLogRecord(xlogreader) &&
xlogreader->EndRecPtr <= end_lsn)
{
CHECK_FOR_INTERRUPTS();
if (!XLogRecHasAnyBlockRefs(xlogreader))
continue;
/* Use the tmp context so we can clean up after each tuple is done */
old_cxt = MemoryContextSwitchTo(tmp_cxt);
@ -385,8 +398,6 @@ pg_get_wal_block_info(PG_FUNCTION_ARGS)
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);
MemoryContextReset(tmp_cxt);
CHECK_FOR_INTERRUPTS();
}
MemoryContextDelete(tmp_cxt);
@ -483,8 +494,6 @@ GetWALRecordsInfo(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
#define PG_GET_WAL_RECORDS_INFO_COLS 11
XLogReaderState *xlogreader;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
Datum values[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
bool nulls[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
MemoryContext old_cxt;
MemoryContext tmp_cxt;
@ -501,6 +510,9 @@ GetWALRecordsInfo(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
while (ReadNextXLogRecord(xlogreader) &&
xlogreader->EndRecPtr <= end_lsn)
{
Datum values[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
bool nulls[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
/* Use the tmp context so we can clean up after each tuple is done */
old_cxt = MemoryContextSwitchTo(tmp_cxt);